Early humans may have lived in the Philippines as early as 709,000 years ago, according to a paper published in Nature this week. Evidence of hominin activity comes in the form of rhinoceros bones that show signs of butchering by stone tools.

Stone tools and the remains of large, likely Pleistocene-age animals were separately discovered on Luzon in the 1950s, hinting that the Philippine island may have been colonized by early humans in the Middle Pleistocene (between 781,000 and 126,000 years ago). However, securely dated evidence in support of this has been lacking. Until now, the earliest certain evidence of hominins in the Philippines came from a single foot bone, found in the Sierra Madre mountains, dated to 67,000 years ago.

Thomas Ingicco and colleagues report the discovery of over 400 bones - including the 75%-complete remains of a single rhinoceros - associated with 57 knapped stone tools from a site in the Cagayan Valley of northern Luzon. Thirteen of the rhino’s bones display cut marks and two show evidence of being struck to release marrow. The authors also unearthed the remains of brown deer, monitor lizards, freshwater turtles and stegodons - an extinct genus similar to elephants and mammoths. The authors date the remains to around 709,000 years ago.

Although the exact species of the stone tools’ owners remains a mystery, the findings suggest that, as with the nearby South East Asian islands of Flores and Sulawesi, early humans had reached the Philippines by the early Middle Pleistocene - long before modern humans. This adds another sea-crossing to the question of whether early hominin toolmakers were unexpectedly capable of constructing simple watercraft.